// © 2016 and later: Unicode, Inc. and others.
// License & terms of use: http://www.unicode.org/copyright.html
/*
 *******************************************************************************
 * Copyright (C) 2003-2016, International Business Machines Corporation and    *
 * others. All Rights Reserved.                                                *
 *******************************************************************************
 */

package com.ibm.icu.text;

import com.ibm.icu.impl.IDNA2003;
import com.ibm.icu.impl.UTS46;
import java.util.Collections;
import java.util.EnumSet;
import java.util.Set;

/**
 * Abstract base class for IDNA processing. See http://www.unicode.org/reports/tr46/ and
 * http://www.ietf.org/rfc/rfc3490.txt
 *
 * <p>The IDNA class is not intended for public subclassing.
 *
 * <p>The non-static methods implement UTS #46 and IDNA2008. IDNA2008 is implemented according to
 * UTS #46, see {@link #getUTS46Instance(int)}.
 *
 * <p>IDNA2003 is obsolete. The static methods implement IDNA2003. They are all deprecated.
 *
 * <p>IDNA2003 API Overview:
 *
 * <p>The static IDNA API methods implement the IDNA protocol as defined in the <a
 * href="http://www.ietf.org/rfc/rfc3490.txt">IDNA RFC</a>. The draft defines 2 operations: ToASCII
 * and ToUnicode. Domain labels containing non-ASCII code points are required to be processed by
 * ToASCII operation before passing it to resolver libraries. Domain names that are obtained from
 * resolver libraries are required to be processed by ToUnicode operation before displaying the
 * domain name to the user. IDNA requires that implementations process input strings with <a
 * href="http://www.ietf.org/rfc/rfc3491.txt">Nameprep</a>, which is a profile of <a
 * href="http://www.ietf.org/rfc/rfc3454.txt">Stringprep</a> , and then with <a
 * href="http://www.ietf.org/rfc/rfc3492.txt">Punycode</a>. Implementations of IDNA MUST fully
 * implement Nameprep and Punycode; neither Nameprep nor Punycode are optional. The input and output
 * of ToASCII and ToUnicode operations are Unicode and are designed to be chainable, i.e., applying
 * ToASCII or ToUnicode operations multiple times to an input string will yield the same result as
 * applying the operation once. ToUnicode(ToUnicode(ToUnicode...(ToUnicode(string)))) ==
 * ToUnicode(string) ToASCII(ToASCII(ToASCII...(ToASCII(string))) == ToASCII(string).
 *
 * @author Ram Viswanadha, Markus Scherer
 * @stable ICU 2.8
 */
public abstract class IDNA {
    /**
     * Default options value: UTS #46 nontransitional processing. For use in static worker and
     * factory methods.
     *
     * <p>Since ICU 76, this is the same as {@link #NONTRANSITIONAL_TO_ASCII} | {@link
     * #NONTRANSITIONAL_TO_UNICODE}, corresponding to Unicode 15.1 UTS #46 deprecating transitional
     * processing. (These options are ignored by the IDNA2003 implementation.)
     *
     * <p>Before ICU 76, this constant did not set any of the options.
     *
     * @stable ICU 2.8
     */
    public static final int DEFAULT = 0x30;

    /**
     * Option to allow unassigned code points in domain names and labels. For use in static worker
     * and factory methods.
     *
     * <p>This option is ignored by the UTS46 implementation. (UTS #46 disallows unassigned code
     * points.)
     *
     * @deprecated ICU 55 Use UTS 46 instead via {@link #getUTS46Instance(int)}.
     */
    @Deprecated public static final int ALLOW_UNASSIGNED = 1;

    /**
     * Option to check whether the input conforms to the STD3 ASCII rules, for example the
     * restriction of labels to LDH characters (ASCII Letters, Digits and Hyphen-Minus). For use in
     * static worker and factory methods.
     *
     * @stable ICU 2.8
     */
    public static final int USE_STD3_RULES = 2;

    /**
     * IDNA option to check for whether the input conforms to the BiDi rules. For use in static
     * worker and factory methods.
     *
     * <p>This option is ignored by the IDNA2003 implementation. (IDNA2003 always performs a BiDi
     * check.)
     *
     * @stable ICU 4.6
     */
    public static final int CHECK_BIDI = 4;

    /**
     * IDNA option to check for whether the input conforms to the CONTEXTJ rules. For use in static
     * worker and factory methods.
     *
     * <p>This option is ignored by the IDNA2003 implementation. (The CONTEXTJ check is new in
     * IDNA2008.)
     *
     * @stable ICU 4.6
     */
    public static final int CHECK_CONTEXTJ = 8;

    /**
     * IDNA option for nontransitional processing in ToASCII(). For use in static worker and factory
     * methods.
     *
     * <p>By default, ToASCII() uses transitional processing. Unicode 15.1 UTS #46 deprecated
     * transitional processing.
     *
     * <p>This option is ignored by the IDNA2003 implementation. (This is only relevant for
     * compatibility of newer IDNA implementations with IDNA2003.)
     *
     * @stable ICU 4.6
     */
    public static final int NONTRANSITIONAL_TO_ASCII = 0x10;

    /**
     * IDNA option for nontransitional processing in ToUnicode(). For use in static worker and
     * factory methods.
     *
     * <p>By default, ToUnicode() uses transitional processing. Unicode 15.1 UTS #46 deprecated
     * transitional processing.
     *
     * <p>This option is ignored by the IDNA2003 implementation. (This is only relevant for
     * compatibility of newer IDNA implementations with IDNA2003.)
     *
     * @stable ICU 4.6
     */
    public static final int NONTRANSITIONAL_TO_UNICODE = 0x20;

    /**
     * IDNA option to check for whether the input conforms to the CONTEXTO rules. For use in static
     * worker and factory methods.
     *
     * <p>This option is ignored by the IDNA2003 implementation. (The CONTEXTO check is new in
     * IDNA2008.)
     *
     * <p>This is for use by registries for IDNA2008 conformance. UTS #46 does not require the
     * CONTEXTO check.
     *
     * @stable ICU 49
     */
    public static final int CHECK_CONTEXTO = 0x40;

    /**
     * Returns an IDNA instance which implements UTS #46. Returns an unmodifiable instance, owned by
     * the caller. Cache it for multiple operations, and delete it when done. The instance is
     * thread-safe, that is, it can be used concurrently.
     *
     * <p>UTS #46 defines Unicode IDNA Compatibility Processing, updated to the latest version of
     * Unicode and compatible with both IDNA2003 and IDNA2008.
     *
     * <p>The worker functions use transitional processing, including deviation mappings, unless
     * {@link #NONTRANSITIONAL_TO_ASCII} or {@link #NONTRANSITIONAL_TO_UNICODE} is used in which
     * case the deviation characters are passed through without change. <b>Unicode 15.1 UTS #46
     * deprecated transitional processing.</b>
     *
     * <p>Disallowed characters are mapped to U+FFFD.
     *
     * <p>Operations with the UTS #46 instance do not support the ALLOW_UNASSIGNED option.
     *
     * <p>By default, the UTS #46 implementation allows all ASCII characters (as valid or mapped).
     * When the USE_STD3_RULES option is used, ASCII characters other than letters, digits, hyphen
     * (LDH) and dot/full stop are disallowed and mapped to U+FFFD.
     *
     * @param options Bit set to modify the processing and error checking. These should include
     *     {@link IDNA#DEFAULT}, or {@link IDNA#NONTRANSITIONAL_TO_ASCII} | {@link
     *     IDNA#NONTRANSITIONAL_TO_UNICODE}.
     * @return the UTS #46 IDNA instance, if successful
     * @stable ICU 4.6
     */
    public static IDNA getUTS46Instance(int options) {
        return new UTS46(options);
    }

    /**
     * Converts a single domain name label into its ASCII form for DNS lookup. If any processing
     * step fails, then info.hasErrors() will be true and the result might not be an ASCII string.
     * The label might be modified according to the types of errors. Labels with severe errors will
     * be left in (or turned into) their Unicode form.
     *
     * @param label Input domain name label
     * @param dest Destination string object
     * @param info Output container of IDNA processing details.
     * @return dest
     * @stable ICU 4.6
     */
    public abstract StringBuilder labelToASCII(CharSequence label, StringBuilder dest, Info info);

    /**
     * Converts a single domain name label into its Unicode form for human-readable display. If any
     * processing step fails, then info.hasErrors() will be true. The label might be modified
     * according to the types of errors.
     *
     * @param label Input domain name label
     * @param dest Destination string object
     * @param info Output container of IDNA processing details.
     * @return dest
     * @stable ICU 4.6
     */
    public abstract StringBuilder labelToUnicode(CharSequence label, StringBuilder dest, Info info);

    /**
     * Converts a whole domain name into its ASCII form for DNS lookup. If any processing step
     * fails, then info.hasErrors() will be true and the result might not be an ASCII string. The
     * domain name might be modified according to the types of errors. Labels with severe errors
     * will be left in (or turned into) their Unicode form.
     *
     * @param name Input domain name
     * @param dest Destination string object
     * @param info Output container of IDNA processing details.
     * @return dest
     * @stable ICU 4.6
     */
    public abstract StringBuilder nameToASCII(CharSequence name, StringBuilder dest, Info info);

    /**
     * Converts a whole domain name into its Unicode form for human-readable display. If any
     * processing step fails, then info.hasErrors() will be true. The domain name might be modified
     * according to the types of errors.
     *
     * @param name Input domain name
     * @param dest Destination string object
     * @param info Output container of IDNA processing details.
     * @return dest
     * @stable ICU 4.6
     */
    public abstract StringBuilder nameToUnicode(CharSequence name, StringBuilder dest, Info info);

    /**
     * Output container for IDNA processing errors. The Info class is not suitable for subclassing.
     *
     * @stable ICU 4.6
     */
    public static final class Info {
        /**
         * Constructor.
         *
         * @stable ICU 4.6
         */
        public Info() {
            errors = EnumSet.noneOf(Error.class);
            labelErrors = EnumSet.noneOf(Error.class);
            isTransDiff = false;
            isBiDi = false;
            isOkBiDi = true;
        }

        /**
         * Were there IDNA processing errors?
         *
         * @return true if there were processing errors
         * @stable ICU 4.6
         */
        public boolean hasErrors() {
            return !errors.isEmpty();
        }

        /**
         * Returns a set indicating IDNA processing errors.
         *
         * @return set of processing errors (modifiable, and not null)
         * @stable ICU 4.6
         */
        public Set<Error> getErrors() {
            return errors;
        }

        /**
         * Returns true if transitional and nontransitional processing produce different results.
         * This is the case when the input label or domain name contains one or more deviation
         * characters outside a Punycode label (see UTS #46).
         *
         * <ul>
         *   <li>With nontransitional processing, such characters are copied to the destination
         *       string.
         *   <li>With transitional processing, such characters are mapped (sharp s/sigma) or removed
         *       (joiner/nonjoiner).
         * </ul>
         *
         * @return true if transitional and nontransitional processing produce different results
         * @stable ICU 4.6
         */
        public boolean isTransitionalDifferent() {
            return isTransDiff;
        }

        private void reset() {
            errors.clear();
            labelErrors.clear();
            isTransDiff = false;
            isBiDi = false;
            isOkBiDi = true;
        }

        private EnumSet<Error> errors, labelErrors;
        private boolean isTransDiff;
        private boolean isBiDi;
        private boolean isOkBiDi;
    }

    // The following protected methods give IDNA subclasses access to the private IDNAInfo fields.
    // The IDNAInfo also provides intermediate state that is publicly invisible,
    // avoiding the allocation of another worker object.
    /**
     * @internal
     * @deprecated This API is ICU internal only.
     */
    @Deprecated
    protected static void resetInfo(Info info) {
        info.reset();
    }

    /**
     * @internal
     * @deprecated This API is ICU internal only.
     */
    @Deprecated
    protected static boolean hasCertainErrors(Info info, EnumSet<Error> errors) {
        return !info.errors.isEmpty() && !Collections.disjoint(info.errors, errors);
    }

    /**
     * @internal
     * @deprecated This API is ICU internal only.
     */
    @Deprecated
    protected static boolean hasCertainLabelErrors(Info info, EnumSet<Error> errors) {
        return !info.labelErrors.isEmpty() && !Collections.disjoint(info.labelErrors, errors);
    }

    /**
     * @internal
     * @deprecated This API is ICU internal only.
     */
    @Deprecated
    protected static void addLabelError(Info info, Error error) {
        info.labelErrors.add(error);
    }

    /**
     * @internal
     * @deprecated This API is ICU internal only.
     */
    @Deprecated
    protected static void promoteAndResetLabelErrors(Info info) {
        if (!info.labelErrors.isEmpty()) {
            info.errors.addAll(info.labelErrors);
            info.labelErrors.clear();
        }
    }

    /**
     * @internal
     * @deprecated This API is ICU internal only.
     */
    @Deprecated
    protected static void addError(Info info, Error error) {
        info.errors.add(error);
    }

    /**
     * @internal
     * @deprecated This API is ICU internal only.
     */
    @Deprecated
    protected static void setTransitionalDifferent(Info info) {
        info.isTransDiff = true;
    }

    /**
     * @internal
     * @deprecated This API is ICU internal only.
     */
    @Deprecated
    protected static void setBiDi(Info info) {
        info.isBiDi = true;
    }

    /**
     * @internal
     * @deprecated This API is ICU internal only.
     */
    @Deprecated
    protected static boolean isBiDi(Info info) {
        return info.isBiDi;
    }

    /**
     * @internal
     * @deprecated This API is ICU internal only.
     */
    @Deprecated
    protected static void setNotOkBiDi(Info info) {
        info.isOkBiDi = false;
    }

    /**
     * @internal
     * @deprecated This API is ICU internal only.
     */
    @Deprecated
    protected static boolean isOkBiDi(Info info) {
        return info.isOkBiDi;
    }

    /**
     * IDNA error bit set values. When a domain name or label fails a processing step or does not
     * meet the validity criteria, then one or more of these error bits are set.
     *
     * @stable ICU 4.6
     */
    public static enum Error {
        /**
         * A non-final domain name label (or the whole domain name) is empty.
         *
         * @stable ICU 4.6
         */
        EMPTY_LABEL,
        /**
         * A domain name label is longer than 63 bytes. (See STD13/RFC1034 3.1. Name space
         * specifications and terminology.) This is only checked in ToASCII operations, and only if
         * the output label is all-ASCII.
         *
         * @stable ICU 4.6
         */
        LABEL_TOO_LONG,
        /**
         * A domain name is longer than 255 bytes in its storage form. (See STD13/RFC1034 3.1. Name
         * space specifications and terminology.) This is only checked in ToASCII operations, and
         * only if the output domain name is all-ASCII.
         *
         * @stable ICU 4.6
         */
        DOMAIN_NAME_TOO_LONG,
        /**
         * A label starts with a hyphen-minus ('-').
         *
         * @stable ICU 4.6
         */
        LEADING_HYPHEN,
        /**
         * A label ends with a hyphen-minus ('-').
         *
         * @stable ICU 4.6
         */
        TRAILING_HYPHEN,
        /**
         * A label contains hyphen-minus ('-') in the third and fourth positions.
         *
         * @stable ICU 4.6
         */
        HYPHEN_3_4,
        /**
         * A label starts with a combining mark.
         *
         * @stable ICU 4.6
         */
        LEADING_COMBINING_MARK,
        /**
         * A label or domain name contains disallowed characters.
         *
         * @stable ICU 4.6
         */
        DISALLOWED,
        /**
         * A label starts with "xn--" but does not contain valid Punycode. That is, an xn-- label
         * failed Punycode decoding.
         *
         * @stable ICU 4.6
         */
        PUNYCODE,
        /**
         * A label contains a dot=full stop. This can occur in an input string for a single-label
         * function.
         *
         * @stable ICU 4.6
         */
        LABEL_HAS_DOT,
        /**
         * An ACE label does not contain a valid label string. The label was successfully ACE
         * (Punycode) decoded but the resulting string had severe validation errors. For example, it
         * might contain characters that are not allowed in ACE labels, or it might not be
         * normalized.
         *
         * @stable ICU 4.6
         */
        INVALID_ACE_LABEL,
        /**
         * A label does not meet the IDNA BiDi requirements (for right-to-left characters).
         *
         * @stable ICU 4.6
         */
        BIDI,
        /**
         * A label does not meet the IDNA CONTEXTJ requirements.
         *
         * @stable ICU 4.6
         */
        CONTEXTJ,
        /**
         * A label does not meet the IDNA CONTEXTO requirements for punctuation characters. Some
         * punctuation characters "Would otherwise have been DISALLOWED" but are allowed in certain
         * contexts. (RFC 5892)
         *
         * @stable ICU 49
         */
        CONTEXTO_PUNCTUATION,
        /**
         * A label does not meet the IDNA CONTEXTO requirements for digits. Arabic-Indic Digits
         * (U+066x) must not be mixed with Extended Arabic-Indic Digits (U+06Fx).
         *
         * @stable ICU 49
         */
        CONTEXTO_DIGITS
    }

    /**
     * Sole constructor. (For invocation by subclass constructors, typically implicit.)
     *
     * @internal
     * @deprecated This API is ICU internal only.
     */
    @Deprecated
    protected IDNA() {}

    /* IDNA2003 API ------------------------------------------------------------- */

    /**
     * IDNA2003: This function implements the ToASCII operation as defined in the IDNA RFC. This
     * operation is done on <b>single labels</b> before sending it to something that expects ASCII
     * names. A label is an individual part of a domain name. Labels are usually separated by dots;
     * e.g." "www.example.com" is composed of 3 labels "www","example", and "com".
     *
     * @param src The input string to be processed
     * @param options A bit set of options: - IDNA.DEFAULT Use default options, i.e., do not process
     *     unassigned code points and do not use STD3 ASCII rules If unassigned code points are
     *     found the operation fails with StringPrepParseException.
     *     <p>- IDNA.ALLOW_UNASSIGNED Unassigned values can be converted to ASCII for query
     *     operations If this option is set, the unassigned code points are in the input are treated
     *     as normal Unicode code points.
     *     <p>- IDNA.USE_STD3_RULES Use STD3 ASCII rules for host name syntax restrictions If this
     *     option is set and the input does not satisfy STD3 rules, the operation will fail with
     *     ParseException
     * @return StringBuffer the converted String
     * @throws StringPrepParseException When an error occurs for parsing a string.
     * @deprecated ICU 55 Use UTS 46 instead via {@link #getUTS46Instance(int)}.
     */
    @Deprecated
    public static StringBuffer convertToASCII(String src, int options)
            throws StringPrepParseException {
        UCharacterIterator iter = UCharacterIterator.getInstance(src);
        return convertToASCII(iter, options);
    }

    /**
     * IDNA2003: This function implements the ToASCII operation as defined in the IDNA RFC. This
     * operation is done on <b>single labels</b> before sending it to something that expects ASCII
     * names. A label is an individual part of a domain name. Labels are usually separated by dots;
     * e.g." "www.example.com" is composed of 3 labels "www","example", and "com".
     *
     * @param src The input string as StringBuffer to be processed
     * @param options A bit set of options: - IDNA.DEFAULT Use default options, i.e., do not process
     *     unassigned code points and do not use STD3 ASCII rules If unassigned code points are
     *     found the operation fails with ParseException.
     *     <p>- IDNA.ALLOW_UNASSIGNED Unassigned values can be converted to ASCII for query
     *     operations If this option is set, the unassigned code points are in the input are treated
     *     as normal Unicode code points.
     *     <p>- IDNA.USE_STD3_RULES Use STD3 ASCII rules for host name syntax restrictions If this
     *     option is set and the input does not satisfy STD3 rules, the operation will fail with
     *     ParseException
     * @return StringBuffer the converted String
     * @deprecated ICU 55 Use UTS 46 instead via {@link #getUTS46Instance(int)}.
     */
    @Deprecated
    public static StringBuffer convertToASCII(StringBuffer src, int options)
            throws StringPrepParseException {
        UCharacterIterator iter = UCharacterIterator.getInstance(src);
        return convertToASCII(iter, options);
    }

    /**
     * IDNA2003: This function implements the ToASCII operation as defined in the IDNA RFC. This
     * operation is done on <b>single labels</b> before sending it to something that expects ASCII
     * names. A label is an individual part of a domain name. Labels are usually separated by dots;
     * e.g." "www.example.com" is composed of 3 labels "www","example", and "com".
     *
     * @param src The input string as UCharacterIterator to be processed
     * @param options A bit set of options: - IDNA.DEFAULT Use default options, i.e., do not process
     *     unassigned code points and do not use STD3 ASCII rules If unassigned code points are
     *     found the operation fails with ParseException.
     *     <p>- IDNA.ALLOW_UNASSIGNED Unassigned values can be converted to ASCII for query
     *     operations If this option is set, the unassigned code points are in the input are treated
     *     as normal Unicode code points.
     *     <p>- IDNA.USE_STD3_RULES Use STD3 ASCII rules for host name syntax restrictions If this
     *     option is set and the input does not satisfy STD3 rules, the operation will fail with
     *     ParseException
     * @return StringBuffer the converted String
     * @deprecated ICU 55 Use UTS 46 instead via {@link #getUTS46Instance(int)}.
     */
    @Deprecated
    public static StringBuffer convertToASCII(UCharacterIterator src, int options)
            throws StringPrepParseException {
        return IDNA2003.convertToASCII(src, options);
    }

    /**
     * IDNA2003: Convenience function that implements the IDNToASCII operation as defined in the
     * IDNA RFC. This operation is done on complete domain names, e.g: "www.example.com". It is
     * important to note that this operation can fail. If it fails, then the input domain name
     * cannot be used as an Internationalized Domain Name and the application should have methods
     * defined to deal with the failure.
     *
     * <p><b>Note:</b> IDNA RFC specifies that a conformant application should divide a domain name
     * into separate labels, decide whether to apply allowUnassigned and useSTD3ASCIIRules on each,
     * and then convert. This function does not offer that level of granularity. The options once
     * set will apply to all labels in the domain name
     *
     * @param src The input string as UCharacterIterator to be processed
     * @param options A bit set of options: - IDNA.DEFAULT Use default options, i.e., do not process
     *     unassigned code points and do not use STD3 ASCII rules If unassigned code points are
     *     found the operation fails with ParseException.
     *     <p>- IDNA.ALLOW_UNASSIGNED Unassigned values can be converted to ASCII for query
     *     operations If this option is set, the unassigned code points are in the input are treated
     *     as normal Unicode code points.
     *     <p>- IDNA.USE_STD3_RULES Use STD3 ASCII rules for host name syntax restrictions If this
     *     option is set and the input does not satisfy STD3 rules, the operation will fail with
     *     ParseException
     * @return StringBuffer the converted String
     * @deprecated ICU 55 Use UTS 46 instead via {@link #getUTS46Instance(int)}.
     */
    @Deprecated
    public static StringBuffer convertIDNToASCII(UCharacterIterator src, int options)
            throws StringPrepParseException {
        return convertIDNToASCII(src.getText(), options);
    }

    /**
     * IDNA2003: Convenience function that implements the IDNToASCII operation as defined in the
     * IDNA RFC. This operation is done on complete domain names, e.g: "www.example.com". It is
     * important to note that this operation can fail. If it fails, then the input domain name
     * cannot be used as an Internationalized Domain Name and the application should have methods
     * defined to deal with the failure.
     *
     * <p><b>Note:</b> IDNA RFC specifies that a conformant application should divide a domain name
     * into separate labels, decide whether to apply allowUnassigned and useSTD3ASCIIRules on each,
     * and then convert. This function does not offer that level of granularity. The options once
     * set will apply to all labels in the domain name
     *
     * @param src The input string as a StringBuffer to be processed
     * @param options A bit set of options: - IDNA.DEFAULT Use default options, i.e., do not process
     *     unassigned code points and do not use STD3 ASCII rules If unassigned code points are
     *     found the operation fails with ParseException.
     *     <p>- IDNA.ALLOW_UNASSIGNED Unassigned values can be converted to ASCII for query
     *     operations If this option is set, the unassigned code points are in the input are treated
     *     as normal Unicode code points.
     *     <p>- IDNA.USE_STD3_RULES Use STD3 ASCII rules for host name syntax restrictions If this
     *     option is set and the input does not satisfy STD3 rules, the operation will fail with
     *     ParseException
     * @return StringBuffer the converted String
     * @deprecated ICU 55 Use UTS 46 instead via {@link #getUTS46Instance(int)}.
     */
    @Deprecated
    public static StringBuffer convertIDNToASCII(StringBuffer src, int options)
            throws StringPrepParseException {
        return convertIDNToASCII(src.toString(), options);
    }

    /**
     * IDNA2003: Convenience function that implements the IDNToASCII operation as defined in the
     * IDNA RFC. This operation is done on complete domain names, e.g: "www.example.com". It is
     * important to note that this operation can fail. If it fails, then the input domain name
     * cannot be used as an Internationalized Domain Name and the application should have methods
     * defined to deal with the failure.
     *
     * <p><b>Note:</b> IDNA RFC specifies that a conformant application should divide a domain name
     * into separate labels, decide whether to apply allowUnassigned and useSTD3ASCIIRules on each,
     * and then convert. This function does not offer that level of granularity. The options once
     * set will apply to all labels in the domain name
     *
     * @param src The input string to be processed
     * @param options A bit set of options: - IDNA.DEFAULT Use default options, i.e., do not process
     *     unassigned code points and do not use STD3 ASCII rules If unassigned code points are
     *     found the operation fails with ParseException.
     *     <p>- IDNA.ALLOW_UNASSIGNED Unassigned values can be converted to ASCII for query
     *     operations If this option is set, the unassigned code points are in the input are treated
     *     as normal Unicode code points.
     *     <p>- IDNA.USE_STD3_RULES Use STD3 ASCII rules for host name syntax restrictions If this
     *     option is set and the input does not satisfy STD3 rules, the operation will fail with
     *     ParseException
     * @return StringBuffer the converted String
     * @deprecated ICU 55 Use UTS 46 instead via {@link #getUTS46Instance(int)}.
     */
    @Deprecated
    public static StringBuffer convertIDNToASCII(String src, int options)
            throws StringPrepParseException {
        return IDNA2003.convertIDNToASCII(src, options);
    }

    /**
     * IDNA2003: This function implements the ToUnicode operation as defined in the IDNA RFC. This
     * operation is done on <b>single labels</b> before sending it to something that expects Unicode
     * names. A label is an individual part of a domain name. Labels are usually separated by dots;
     * for e.g." "www.example.com" is composed of 3 labels "www","example", and "com".
     *
     * @param src The input string to be processed
     * @param options A bit set of options: - IDNA.DEFAULT Use default options, i.e., do not process
     *     unassigned code points and do not use STD3 ASCII rules If unassigned code points are
     *     found the operation fails with ParseException.
     *     <p>- IDNA.ALLOW_UNASSIGNED Unassigned values can be converted to ASCII for query
     *     operations If this option is set, the unassigned code points are in the input are treated
     *     as normal Unicode code points.
     *     <p>- IDNA.USE_STD3_RULES Use STD3 ASCII rules for host name syntax restrictions If this
     *     option is set and the input does not satisfy STD3 rules, the operation will fail with
     *     ParseException
     * @return StringBuffer the converted String
     * @deprecated ICU 55 Use UTS 46 instead via {@link #getUTS46Instance(int)}.
     */
    @Deprecated
    public static StringBuffer convertToUnicode(String src, int options)
            throws StringPrepParseException {
        UCharacterIterator iter = UCharacterIterator.getInstance(src);
        return convertToUnicode(iter, options);
    }

    /**
     * IDNA2003: This function implements the ToUnicode operation as defined in the IDNA RFC. This
     * operation is done on <b>single labels</b> before sending it to something that expects Unicode
     * names. A label is an individual part of a domain name. Labels are usually separated by dots;
     * for e.g." "www.example.com" is composed of 3 labels "www","example", and "com".
     *
     * @param src The input string as StringBuffer to be processed
     * @param options A bit set of options: - IDNA.DEFAULT Use default options, i.e., do not process
     *     unassigned code points and do not use STD3 ASCII rules If unassigned code points are
     *     found the operation fails with ParseException.
     *     <p>- IDNA.ALLOW_UNASSIGNED Unassigned values can be converted to ASCII for query
     *     operations If this option is set, the unassigned code points are in the input are treated
     *     as normal Unicode code points.
     *     <p>- IDNA.USE_STD3_RULES Use STD3 ASCII rules for host name syntax restrictions If this
     *     option is set and the input does not satisfy STD3 rules, the operation will fail with
     *     ParseException
     * @return StringBuffer the converted String
     * @deprecated ICU 55 Use UTS 46 instead via {@link #getUTS46Instance(int)}.
     */
    @Deprecated
    public static StringBuffer convertToUnicode(StringBuffer src, int options)
            throws StringPrepParseException {
        UCharacterIterator iter = UCharacterIterator.getInstance(src);
        return convertToUnicode(iter, options);
    }

    /**
     * IDNA2003: Function that implements the ToUnicode operation as defined in the IDNA RFC. This
     * operation is done on <b>single labels</b> before sending it to something that expects Unicode
     * names. A label is an individual part of a domain name. Labels are usually separated by dots;
     * for e.g." "www.example.com" is composed of 3 labels "www","example", and "com".
     *
     * @param src The input string as UCharacterIterator to be processed
     * @param options A bit set of options: - IDNA.DEFAULT Use default options, i.e., do not process
     *     unassigned code points and do not use STD3 ASCII rules If unassigned code points are
     *     found the operation fails with ParseException.
     *     <p>- IDNA.ALLOW_UNASSIGNED Unassigned values can be converted to ASCII for query
     *     operations If this option is set, the unassigned code points are in the input are treated
     *     as normal Unicode code points.
     *     <p>- IDNA.USE_STD3_RULES Use STD3 ASCII rules for host name syntax restrictions If this
     *     option is set and the input does not satisfy STD3 rules, the operation will fail with
     *     ParseException
     * @return StringBuffer the converted String
     * @deprecated ICU 55 Use UTS 46 instead via {@link #getUTS46Instance(int)}.
     */
    @Deprecated
    public static StringBuffer convertToUnicode(UCharacterIterator src, int options)
            throws StringPrepParseException {
        return IDNA2003.convertToUnicode(src, options);
    }

    /**
     * IDNA2003: Convenience function that implements the IDNToUnicode operation as defined in the
     * IDNA RFC. This operation is done on complete domain names, e.g: "www.example.com".
     *
     * <p><b>Note:</b> IDNA RFC specifies that a conformant application should divide a domain name
     * into separate labels, decide whether to apply allowUnassigned and useSTD3ASCIIRules on each,
     * and then convert. This function does not offer that level of granularity. The options once
     * set will apply to all labels in the domain name
     *
     * @param src The input string as UCharacterIterator to be processed
     * @param options A bit set of options: - IDNA.DEFAULT Use default options, i.e., do not process
     *     unassigned code points and do not use STD3 ASCII rules If unassigned code points are
     *     found the operation fails with ParseException.
     *     <p>- IDNA.ALLOW_UNASSIGNED Unassigned values can be converted to ASCII for query
     *     operations If this option is set, the unassigned code points are in the input are treated
     *     as normal Unicode code points.
     *     <p>- IDNA.USE_STD3_RULES Use STD3 ASCII rules for host name syntax restrictions If this
     *     option is set and the input does not satisfy STD3 rules, the operation will fail with
     *     ParseException
     * @return StringBuffer the converted String
     * @deprecated ICU 55 Use UTS 46 instead via {@link #getUTS46Instance(int)}.
     */
    @Deprecated
    public static StringBuffer convertIDNToUnicode(UCharacterIterator src, int options)
            throws StringPrepParseException {
        return convertIDNToUnicode(src.getText(), options);
    }

    /**
     * IDNA2003: Convenience function that implements the IDNToUnicode operation as defined in the
     * IDNA RFC. This operation is done on complete domain names, e.g: "www.example.com".
     *
     * <p><b>Note:</b> IDNA RFC specifies that a conformant application should divide a domain name
     * into separate labels, decide whether to apply allowUnassigned and useSTD3ASCIIRules on each,
     * and then convert. This function does not offer that level of granularity. The options once
     * set will apply to all labels in the domain name
     *
     * @param src The input string as StringBuffer to be processed
     * @param options A bit set of options: - IDNA.DEFAULT Use default options, i.e., do not process
     *     unassigned code points and do not use STD3 ASCII rules If unassigned code points are
     *     found the operation fails with ParseException.
     *     <p>- IDNA.ALLOW_UNASSIGNED Unassigned values can be converted to ASCII for query
     *     operations If this option is set, the unassigned code points are in the input are treated
     *     as normal Unicode code points.
     *     <p>- IDNA.USE_STD3_RULES Use STD3 ASCII rules for host name syntax restrictions If this
     *     option is set and the input does not satisfy STD3 rules, the operation will fail with
     *     ParseException
     * @return StringBuffer the converted String
     * @deprecated ICU 55 Use UTS 46 instead via {@link #getUTS46Instance(int)}.
     */
    @Deprecated
    public static StringBuffer convertIDNToUnicode(StringBuffer src, int options)
            throws StringPrepParseException {
        return convertIDNToUnicode(src.toString(), options);
    }

    /**
     * IDNA2003: Convenience function that implements the IDNToUnicode operation as defined in the
     * IDNA RFC. This operation is done on complete domain names, e.g: "www.example.com".
     *
     * <p><b>Note:</b> IDNA RFC specifies that a conformant application should divide a domain name
     * into separate labels, decide whether to apply allowUnassigned and useSTD3ASCIIRules on each,
     * and then convert. This function does not offer that level of granularity. The options once
     * set will apply to all labels in the domain name
     *
     * @param src The input string to be processed
     * @param options A bit set of options: - IDNA.DEFAULT Use default options, i.e., do not process
     *     unassigned code points and do not use STD3 ASCII rules If unassigned code points are
     *     found the operation fails with ParseException.
     *     <p>- IDNA.ALLOW_UNASSIGNED Unassigned values can be converted to ASCII for query
     *     operations If this option is set, the unassigned code points are in the input are treated
     *     as normal Unicode code points.
     *     <p>- IDNA.USE_STD3_RULES Use STD3 ASCII rules for host name syntax restrictions If this
     *     option is set and the input does not satisfy STD3 rules, the operation will fail with
     *     ParseException
     * @return StringBuffer the converted String
     * @deprecated ICU 55 Use UTS 46 instead via {@link #getUTS46Instance(int)}.
     */
    @Deprecated
    public static StringBuffer convertIDNToUnicode(String src, int options)
            throws StringPrepParseException {
        return IDNA2003.convertIDNToUnicode(src, options);
    }

    /**
     * IDNA2003: Compare two IDN strings for equivalence. This function splits the domain names into
     * labels and compares them. According to IDN RFC, whenever two labels are compared, they are
     * considered equal if and only if their ASCII forms (obtained by applying toASCII) match using
     * an case-insensitive ASCII comparison. Two domain names are considered a match if and only if
     * all labels match regardless of whether label separators match.
     *
     * @param s1 First IDN string as StringBuffer
     * @param s2 Second IDN string as StringBuffer
     * @param options A bit set of options: - IDNA.DEFAULT Use default options, i.e., do not process
     *     unassigned code points and do not use STD3 ASCII rules If unassigned code points are
     *     found the operation fails with ParseException.
     *     <p>- IDNA.ALLOW_UNASSIGNED Unassigned values can be converted to ASCII for query
     *     operations If this option is set, the unassigned code points are in the input are treated
     *     as normal Unicode code points.
     *     <p>- IDNA.USE_STD3_RULES Use STD3 ASCII rules for host name syntax restrictions If this
     *     option is set and the input does not satisfy STD3 rules, the operation will fail with
     *     ParseException
     * @return 0 if the strings are equal, &gt; 0 if s1 &gt; s2 and &lt; 0 if s1 &lt; s2
     * @deprecated ICU 55 Use UTS 46 instead via {@link #getUTS46Instance(int)}.
     */
    @Deprecated
    public static int compare(StringBuffer s1, StringBuffer s2, int options)
            throws StringPrepParseException {
        if (s1 == null || s2 == null) {
            throw new IllegalArgumentException("One of the source buffers is null");
        }
        return IDNA2003.compare(s1.toString(), s2.toString(), options);
    }

    /**
     * IDNA2003: Compare two IDN strings for equivalence. This function splits the domain names into
     * labels and compares them. According to IDN RFC, whenever two labels are compared, they are
     * considered equal if and only if their ASCII forms (obtained by applying toASCII) match using
     * an case-insensitive ASCII comparison. Two domain names are considered a match if and only if
     * all labels match regardless of whether label separators match.
     *
     * @param s1 First IDN string
     * @param s2 Second IDN string
     * @param options A bit set of options: - IDNA.DEFAULT Use default options, i.e., do not process
     *     unassigned code points and do not use STD3 ASCII rules If unassigned code points are
     *     found the operation fails with ParseException.
     *     <p>- IDNA.ALLOW_UNASSIGNED Unassigned values can be converted to ASCII for query
     *     operations If this option is set, the unassigned code points are in the input are treated
     *     as normal Unicode code points.
     *     <p>- IDNA.USE_STD3_RULES Use STD3 ASCII rules for host name syntax restrictions If this
     *     option is set and the input does not satisfy STD3 rules, the operation will fail with
     *     ParseException
     * @return 0 if the strings are equal, &gt; 0 if s1 &gt; s2 and &lt; 0 if s1 &lt; s2
     * @deprecated ICU 55 Use UTS 46 instead via {@link #getUTS46Instance(int)}.
     */
    @Deprecated
    public static int compare(String s1, String s2, int options) throws StringPrepParseException {
        if (s1 == null || s2 == null) {
            throw new IllegalArgumentException("One of the source buffers is null");
        }
        return IDNA2003.compare(s1, s2, options);
    }

    /**
     * IDNA2003: Compare two IDN strings for equivalence. This function splits the domain names into
     * labels and compares them. According to IDN RFC, whenever two labels are compared, they are
     * considered equal if and only if their ASCII forms (obtained by applying toASCII) match using
     * an case-insensitive ASCII comparison. Two domain names are considered a match if and only if
     * all labels match regardless of whether label separators match.
     *
     * @param s1 First IDN string as UCharacterIterator
     * @param s2 Second IDN string as UCharacterIterator
     * @param options A bit set of options: - IDNA.DEFAULT Use default options, i.e., do not process
     *     unassigned code points and do not use STD3 ASCII rules If unassigned code points are
     *     found the operation fails with ParseException.
     *     <p>- IDNA.ALLOW_UNASSIGNED Unassigned values can be converted to ASCII for query
     *     operations If this option is set, the unassigned code points are in the input are treated
     *     as normal Unicode code points.
     *     <p>- IDNA.USE_STD3_RULES Use STD3 ASCII rules for host name syntax restrictions If this
     *     option is set and the input does not satisfy STD3 rules, the operation will fail with
     *     ParseException
     * @return 0 if the strings are equal, &gt; 0 if i1 &gt; i2 and &lt; 0 if i1 &lt; i2
     * @deprecated ICU 55 Use UTS 46 instead via {@link #getUTS46Instance(int)}.
     */
    @Deprecated
    public static int compare(UCharacterIterator s1, UCharacterIterator s2, int options)
            throws StringPrepParseException {
        if (s1 == null || s2 == null) {
            throw new IllegalArgumentException("One of the source buffers is null");
        }
        return IDNA2003.compare(s1.getText(), s2.getText(), options);
    }
}
